Composite molded caster wheels have been provided for many years. Generally these include a relatively rigid central hub surrounded by a softer floor engaging tread to provide greater traction with less wheel noise while at the same time maintaining a high caster load capacity. However, the amount of resiliency in these prior "soft" treads has been severely limited because the softer the plastic selected for the tread, the more difficult it is to anchor the tread solidly to the hub.
For this reason, most prior composite molded caster wheels have required relatively rigid treads, and in many cases, it has been found necessary to mold the tread around the hub including its side surfaces rather than merely about its periphery.
One attempt to solve the problem is found in the Greene U.S. Pat. No. 4,067,083, wherein the tread material is molded around a continuous auxilliary rim about the periphery of the hub. This arrangement does not completely lock the tread to the hub in all directions.
It is a primary object of the present invention to ameliorate the problems noted above in the manufacture of molded caster wheels having a soft outer tread.